1. Field of the Invention
The present invention relates to a speaker, particularly to a dynamic speaker to be mounted on a printed circuit board.
2. Description of the Related Art
A dynamic speaker is conventionally known among the types of a speaker. As shown in JP-A-6-178390, a dynamic speaker comprises a diaphragm having a voice coil attached on the back surface, and a magnetic circuit structure disposed on the back side of the diaphragm and adapted to support the diaphragm at the periphery thereof.
As shown in FIG. 9, an insulating ring 122 is attached to the front surface of a diaphragm 116 at the periphery thereof and thereby the diaphragm 116 is easily supported by a magnetic circuit frame 114. A pair of terminal members 124 are supported by the insulating ring 122, and thereby a pair of lead wires 118a drawn from a voice coil 118 are connected or fixed to the pair of terminal members 124.
Conventionally, a speaker 110 is first assembled in a holder 150 and then the holder 150 is fixed to a printed circuit board 102. The speaker 110 is housed in the holder 150 with the front side of the speaker 110 facing in the opposite direction to the printed circuit board 102. The holder 150, as shown in FIG. 9, comprises a holder body 152 and a cover 154. The speaker 110 is put tightly therebetween, and then the holder body 152 and the cover 154 are bonded.
Since the conventional speaker 110 is set in the holder 150 with the front side of the speaker 110 facing in the opposite direction to the printed circuit board 102, it has a disadvantage in that a lead wire fixing portion 124a and a conductive portion 124b (a portion connected to a conductor 104 of the printed circuit board 102 for continuity) of each of the terminal members 124 need be protruded backward with respect to the insulating ring 122.
This structure compels each of the terminal members 124 to be bent and formed in the shape of a letter xe2x80x9cJxe2x80x9d. The terminal members 124 therefore need be long and complicated in design, causing an increase of the cost of the speaker 110.
Since the front side of the speaker faces in the opposite direction to the printed circuit board 102, it likely happens that the operator unintentionally touches the diaphragm 116 in mounting the speaker on the printed circuit board, causing a damage thereof.
An object of the present invention is to provide a low cost dynamic speaker which effectively prevents a damage of the diaphragm when the speaker is mounted on the printed circuit board.
The speaker of the present invention achieves the object by providing a terminal member of an improved structure.
According to an aspect of the present invention, there is provided a speaker to be mounted on a printed circuit board comprising:
a diaphragm;
a voice coil attached to the back surface of the diaphragm;
an insulating member attached to the front surface of the diaphragm at the periphery of the diaphragm; and
a pair of terminal members supported by the insulating member, each of the pair of terminal members having a lead wire fixing portion for fixing an end of a lead wire drawn from the voice coil and a conducting portion for securing continuity of the lead wire with a conductor of the printed circuit board;
wherein the conducting portion of each of the terminal members is protruded forward beyond the front end of the insulating member.
The printed circuit board is not limited to the one as herein described. As far as it has a conductor connectable to the terminal members, any type of the printed circuit boards is applicable to the present invention.
The conductor may be formed either of the front side and the back side of the printed circuit board.
The diaphragm is not limited to the one as herein described. As far as it is adaptable as an element of a dynamic speaker, any type of the diaphragm is applicable to the present invention.
The voice coil is not limited to the one as herein described. As far as it is adaptable as an element of a dynamic speaker, any type of the voice coil is applicable to the present invention.
The insulating member is not limited to the one as herein described. As far as it is made of insulating material and adaptable to be attached to the front surface of the diaphragm at the periphery thereof, it may have the shape of a block, or alternatively it may be a ring extending along the periphery of the diaphragm.
According to the speaker of the present invention, the conducting portion of each of the terminal members is protruded forward beyond the front end of the insulating member. This structure has the following advantages.
Compared with the conventional terminal member having the shape of a letter of xe2x80x9cJxe2x80x9d for continuity with the conductor of the printed circuit board, the terminal member of the present invention is simply formed to be straight and short, thus contributing to reduction in cost of the speaker.
Further, when the speaker is mounted on the printed circuit board via the holder, the front side of the speaker faces the printed circuit board. This effectively prevents the operator from unintentionally touching the diaphragm during mounting operation, considerably reducing a risk of damage thereof.
Further, since the speaker is adapted to be directly in contact with the printed circuit board by a mounting structure of the present invention, the mounting height of the speaker on the printed circuit board is lowered than in the conventional structure.
The insulating member may have the shape of a ring extended along the periphery of the diaphragm, and the front end of the insulating member may comprise an annular flat surface.
Such insulating member enables the speaker to be closely attached to the printed circuit board at the entire periphery. In state where the speaker is mounted on the printed circuit board, the annular flat surface of the insulating ring abuts against the back surface of the printed circuit board so as to close a circular opening formed in the printed circuit board. The printed circuit board serves as a baffle plate, isolating the front space from the back space of the speaker and thus preventing a backward sound from traveling toward the front side of the speaker to interfere with a forward sound. This improves the sound characteristics of the speaker.
The pair of terminal members may be fixed to the insulating member by insert molding. This method firmly secures the terminal member to the insulating member, and also enables a simplified manufacturing process of the speaker.
Each of the terminal members may comprise a terminal pin penetrating the insulating member. This enables a simple structure and further reduces the cost of the speaker.
The conducting portion of each of the terminal members may be made of elastic material. This structure attains continuity across the terminal members and the printed circuit board without soldering operation and thereby facilitates the assembly of the speaker to the printed circuit board. The elastic terminal member comprises, for example, a plate spring and a coil spring.